Fifty-six years ago this month, the Minnesota State Fair was cancelled. The reason was polio. Health officials worried large gatherings helped spread the disease.

Polio was crippling thousands and there was no known cure or prevention. Throughout the 1940s and early '50s, polio struck 15,000 Minnesotans - 900 died. Those who survived were consigned to a life with metal braces, crutches and deformed limbs.

Then Elizabeth Kenny arrived. The single-minded, self-taught nurse from Australia brought to Minnesota a treatment that got paralyzed polio victims up and walking.

Elizabeth Kenny emerged from obscurity and became America's most admired woman. Her remarkable story has few parallels in medical history.